It is well-known that DNA (deoxyribonucleic acid) has a double helix structure. DNA in aqueous solution is classified into an electrolyte polymer with a continuous length of about 500 angstroms having a negative charge every about 1.5 angstroms. It is also known that a base pair layer and a major groove in the double helix structure of DNA have a selective absorptivity of an aromatic compound having a planer chemical structure.
Conventionally, the process has been disclosed in which a water-insoluble crosslinked polymer of the water-soluble DNA is immobilized on a support by irradiating ultraviolet light with a wavelength of 250 to 270 nm to an aqueous solution of the water-soluble DNA (e.g., DNA derived from salmon sperm) or a liquid film thereof on the support, or a thin layer of the water-soluble DNA on the support, or a thin layer obtained by concentrating or drying the liquid film of the water-soluble DNA on the support (e.g., see Patent Document 1). According to this process, the ultraviolet light causes a crosslinking reaction of the DNA derived from the salmon sperm to insolubilize in water, and a carcinogenic substance and an endocrine disturbing chemical composed of the aromatic compound having the planer chemical structure can be absorbed by this insolubilization technology.
Meanwhile, the present applicant applied the process for producing a liquid crystalline gel by dialyzing the solution of the polymer such as curdlan and DNA in the aqueous solution of a metal cation for a patent (see Japanese Patent Application 2004-249638, International Patent Application PCT/JP2005/015395). Among these liquid crystalline gels produced by the dialysis, in particular, the liquid crystalline gel composed of the curdlan is expected to be practically applied to optical parts and drug carriers because of its characteristic liquid crystal structure. The liquid crystalline gel composed of DNA is expected to be practically applied to environmental purification materials by taking advantage of its absorbable function of environmental pollutants.
Patent document 1: JP 2001-81098 (Claims, [0019], [0022])